The present invention relates to an electrostatographic reproducing apparatus and more particularly to blade cleaning apparatus for use in cleaning an imaging surface of a endless, flexible electrostatographic imaging belt.
In an electrostatographic reproducing apparatus commonly in use today, a photoconductive insulating member is typically charged to uniform potential thereafter exposed to a light image of an original document to be reproduced. The exposure discharges the photoconductive insulating surface in exposed or background areas and creates an electrostatic latent image on the member which corresponds to the image areas contained within the usual document. Subsequently, the electrostatic latent image on the photoconductive insulating surface is made visible by developing the image with developing powder referred to in the art as toner. Most development systems employ a developer material which comprises both charged carrier particles and charged toner particles which triboelectrically adhere to the carrier particles. During development the toner particles are attracted from the carrier particles by the charge pattern of the image areas in the photoconductive insulating area to form a powder image on the photoconductive area. This image may subsequently be transferred to a support surface such as copy paper to which it may be permanently affixed by heating or by the application of pressure.
Many commercial applications of the above process employ the use of the photoconductive insulating member in the form of a belt which is supported about a predetermined path past the plurality of processing stations to ultimately form a reproduced image on copy paper. During the imaging procedure described above, and frequently during the step of transferring toner particles to the copy sheet all the toner is not transferred and some residual toner particles remain adhering to the photoconductive surface after the transfer. Various types of devices have been used in the prior art to clean the imaging surface of this residual toner particles. Such devices include, for example, webs and brushes, foam rollers, and rotating magnets enclosed in a stationary non-magnetic belt or alternatively, stationary magnets enclosed within a rotating non-magnetic shell. In addition, blades of either the wipe or chisel type have been used to remove residual toner from the imaging surface. Cleaning blades have proved particularly satisfactory for cleaning the imaging surfaces on structurally rigid imaging drums which have been conventionally used in a number of commercial applications. This is because the blade may be mounted rigidly against the drum at virtually any position thereof to provide the necessary cleaning force to clean the residual toner. However, in the use of flexible belts supported by a plurality of rolls or arcuate members around the processing path the flexibility of design is limited for the use of a cleaning blade to be in a position adjacent to one of the rolls or arcuate members about which the belt travels to provide adequate support for the belt cleaning action. Furthermore, with the cleaning blade positioned at positions corresponding to the three o'clock, six o'clock and nine o'clock positions around the feeder path of the imaging drum or a photoconductive belt, the residual toner tends to fall away thereby increasing the coefficient of friction between the blade and the imaging surface to such a level that the edge or tip of the blade tends to tuck under thereby causing subsequent cleaning failures. Accordingly, there is a desire to provide a cleaning system for use in a machine employing a belt type photoconductor wherein the necessary force between the blade and the belt is obtained as well as adequate lubrication of the blade tip by the cleaner toner